18M accounts from 8tracks (8tracks.com) were exposed in this breach. Besides email addresses, it included passwords, which makes it a high-risk breach.
Was your email address in this breach?
We display where your address leaked and what went with it. We never store the address.
We don't store your address. It is checked right here against about 1029 breaches, including this one.
Email addressesPasswords
In June 2017, the online playlists service known as 8Tracks suffered a data breach which impacted 18 million accounts. In their disclosure, 8Tracks advised that "the vector for the attack was an employee’s GitHub account, which was not secured using two-factor authentication". Salted SHA-1 password hashes for users who didn't sign up with either Google or Facebook authentication were also included. The data was provided to HIBP by whitehat security researcher and data analyst Adam Davies and contained almost 8 million unique email addresses. The complete set of 18M records was later provided by JimScott.Sec@protonmail.com and updated in HIBP accordingly.
Source: Have I Been Pwned (CC BY 4.0)